Hi, Alexandre. It seems that you are starting to write some project using the ADT technique, on C. Here some link to a book I didn't read. (I never programmed on C). Our lecturers say that this book is not _so_ good, but it is what de facto they want to teach on courses on C, so it is recommended. http://www.cs.technion.ac.il/users/yechiel/CS/Interesting/BugFreeC.html Regards, Dima. On 9/19/07, John Love-Jensen <eljay@xxxxxxxxx> wrote: > Hi Alexandre, > > Taking Dima's solution in conjunction with the way Apple solved their > similar problem by using opaque types in Cocoa and Carbon: > > struct CW_C_MsgUp_s; > typedef struct CW_C_MsgUp_t* CW_C_MsgUp_t; > > struct CW_C_MsgDown_s; > typedef struct CW_C_MsgDown_t* CW_C_MsgDown_t; > > This will insulate your implementation of those opaque types from the public > header files (note that the structs are forward references, and not declared > publically), and allow you some measure of type safety in C. > > Apple uses a factory function to create their opaque types, and for most > opaque types the CFRelease function to destruct them (using a reference > counting mechanism). That's the role that CW_C_MsgUp_new() and > CW_C_MsgDown_new() provides. > > As far as them being pointers... I believe that you will want them to be > pointers baked into the typedef. > > The one change to your code would be to change from this... > > CW_C_MsgUp_t *my_up_msg; > CW_C_MsgDown_t *my_down_msg; > > ...to this... > > CW_C_MsgUp_t my_up_msg; > CW_C_MsgDown_t my_down_msg; > > HTH, > --Eljay > >
